
#include "icon_util.h"

#include "base/file_util.h"
#include "base/file_path.h"
#include "base/logging.h"
#include "base/memory/scoped_ptr.h"
#include "base/win/scoped_handle.h"

#include "SkBitmap.h"

#include "skia/ext/image_operations.h"

#include "size.h"

// Defining the dimensions for the icon images. We store only one value because
// we always resize to a square image; that is, the value 48 means that we are
// going to resize the given bitmap to a 48 by 48 pixels bitmap.
//
// The icon images appear in the icon file in same order in which their
// corresponding dimensions appear in the |icon_dimensions_| array, so it is
// important to keep this array sorted. Also note that the maximum icon image
// size we can handle is 255 by 255.
const int IconUtil::icon_dimensions_[] =
{
    8,    // Recommended by the MSDN as a nice to have icon size.
    10,   // Used by the Shell (e.g. for shortcuts).
    14,   // Recommended by the MSDN as a nice to have icon size.
    16,   // Toolbar, Application and Shell icon sizes.
    22,   // Recommended by the MSDN as a nice to have icon size.
    24,   // Used by the Shell (e.g. for shortcuts).
    32,   // Toolbar, Dialog and Wizard icon size.
    40,   // Quick Launch.
    48,   // Alt+Tab icon size.
    64,   // Recommended by the MSDN as a nice to have icon size.
    96,   // Recommended by the MSDN as a nice to have icon size.
    128   // Used by the Shell (e.g. for shortcuts).
};

HICON IconUtil::CreateHICONFromSkBitmap(const SkBitmap& bitmap)
{
    // Only 32 bit ARGB bitmaps are supported. We also try to perform as many
    // validations as we can on the bitmap.
    SkAutoLockPixels bitmap_lock(bitmap);
    if((bitmap.getConfig()!=SkBitmap::kARGB_8888_Config) ||
        (bitmap.width()<=0) || (bitmap.height()<=0) ||
        (bitmap.getPixels()==NULL))
    {
        return NULL;
    }

    // We start by creating a DIB which we'll use later on in order to create
    // the HICON. We use BITMAPV5HEADER since the bitmap we are about to convert
    // may contain an alpha channel and the V5 header allows us to specify the
    // alpha mask for the DIB.
    BITMAPV5HEADER bitmap_header;
    InitializeBitmapHeader(&bitmap_header, bitmap.width(), bitmap.height());
    void* bits;
    HDC hdc = ::GetDC(NULL);
    HBITMAP dib;
    dib = ::CreateDIBSection(hdc, reinterpret_cast<BITMAPINFO*>(&bitmap_header),
        DIB_RGB_COLORS, &bits, NULL, 0);
    DCHECK(dib);
    ::ReleaseDC(NULL, hdc);
    memcpy(bits, bitmap.getPixels(), bitmap.width()*bitmap.height()*4);

    // Icons are generally created using an AND and XOR masks where the AND
    // specifies boolean transparency (the pixel is either opaque or
    // transparent) and the XOR mask contains the actual image pixels. If the XOR
    // mask bitmap has an alpha channel, the AND monochrome bitmap won't
    // actually be used for computing the pixel transparency. Even though all our
    // bitmap has an alpha channel, Windows might not agree when all alpha values
    // are zero. So the monochrome bitmap is created with all pixels transparent
    // for this case. Otherwise, it is created with all pixels opaque.
    bool bitmap_has_alpha_channel = PixelsHaveAlpha(
        static_cast<const uint32*>(bitmap.getPixels()),
        bitmap.width()*bitmap.height());

    scoped_array<uint8> mask_bits;
    if(!bitmap_has_alpha_channel)
    {
        // Bytes per line with paddings to make it word alignment.
        size_t bytes_per_line = (bitmap.width() + 0xF) / 16 * 2;
        size_t mask_bits_size = bytes_per_line * bitmap.height();

        mask_bits.reset(new uint8[mask_bits_size]);
        DCHECK(mask_bits.get());

        // Make all pixels transparent.
        memset(mask_bits.get(), 0xFF, mask_bits_size);
    }

    HBITMAP mono_bitmap = ::CreateBitmap(bitmap.width(), bitmap.height(),
        1, 1, reinterpret_cast<LPVOID>(mask_bits.get()));
    DCHECK(mono_bitmap);

    ICONINFO icon_info;
    icon_info.fIcon = TRUE;
    icon_info.xHotspot = 0;
    icon_info.yHotspot = 0;
    icon_info.hbmMask = mono_bitmap;
    icon_info.hbmColor = dib;
    HICON icon = ::CreateIconIndirect(&icon_info);
    ::DeleteObject(dib);
    ::DeleteObject(mono_bitmap);
    return icon;
}

SkBitmap* IconUtil::CreateSkBitmapFromHICON(HICON icon, const gfx::Size& s)
{
    // We start with validating parameters.
    ICONINFO icon_info;
    if(!icon || !(::GetIconInfo(icon, &icon_info)) ||
        !icon_info.fIcon || s.IsEmpty())
    {
        return NULL;
    }

    // Allocating memory for the SkBitmap object. We are going to create an ARGB
    // bitmap so we should set the configuration appropriately.
    SkBitmap* bitmap = new SkBitmap;
    DCHECK(bitmap);
    bitmap->setConfig(SkBitmap::kARGB_8888_Config, s.width(), s.height());
    bitmap->allocPixels();
    bitmap->eraseARGB(0, 0, 0, 0);
    SkAutoLockPixels bitmap_lock(*bitmap);

    // Now we should create a DIB so that we can use ::DrawIconEx in order to
    // obtain the icon's image.
    BITMAPV5HEADER h;
    InitializeBitmapHeader(&h, s.width(), s.height());
    HDC dc = ::GetDC(NULL);
    uint32* bits;
    HBITMAP dib = ::CreateDIBSection(dc, reinterpret_cast<BITMAPINFO*>(&h),
        DIB_RGB_COLORS, reinterpret_cast<void**>(&bits), NULL, 0);
    DCHECK(dib);
    HDC dib_dc = CreateCompatibleDC(dc);
    DCHECK(dib_dc);
    ::SelectObject(dib_dc, dib);

    // Windows icons are defined using two different masks. The XOR mask, which
    // represents the icon image and an AND mask which is a monochrome bitmap
    // which indicates the transparency of each pixel.
    //
    // To make things more complex, the icon image itself can be an ARGB bitmap
    // and therefore contain an alpha channel which specifies the transparency
    // for each pixel. Unfortunately, there is no easy way to determine whether
    // or not a bitmap has an alpha channel and therefore constructing the bitmap
    // for the icon is nothing but straightforward.
    //
    // The idea is to read the AND mask but use it only if we know for sure that
    // the icon image does not have an alpha channel. The only way to tell if the
    // bitmap has an alpha channel is by looking through the pixels and checking
    // whether there are non-zero alpha bytes.
    //
    // We start by drawing the AND mask into our DIB.
    size_t num_pixels = s.GetArea();
    memset(bits, 0, num_pixels*4);
    ::DrawIconEx(dib_dc, 0, 0, icon, s.width(), s.height(), 0, NULL, DI_MASK);

    // Capture boolean opacity. We may not use it if we find out the bitmap has
    // an alpha channel.
    bool* opaque = new bool[num_pixels];
    DCHECK(opaque);
    for(size_t i=0; i<num_pixels; ++i)
    {
        opaque[i] = !bits[i];
    }

    // Then draw the image itself which is really the XOR mask.
    memset(bits, 0, num_pixels*4);
    ::DrawIconEx(dib_dc, 0, 0, icon, s.width(), s.height(), 0, NULL, DI_NORMAL);
    memcpy(bitmap->getPixels(), static_cast<void*>(bits), num_pixels*4);

    // Finding out whether the bitmap has an alpha channel.
    bool bitmap_has_alpha_channel = PixelsHaveAlpha(
        static_cast<const uint32*>(bitmap->getPixels()), num_pixels);

    // If the bitmap does not have an alpha channel, we need to build it using
    // the previously captured AND mask. Otherwise, we are done.
    if(!bitmap_has_alpha_channel)
    {
        uint32* p = static_cast<uint32*>(bitmap->getPixels());
        for(size_t i=0; i<num_pixels; ++p,++i)
        {
            DCHECK_EQ((*p & 0xff000000), 0u);
            if(opaque[i])
            {
                *p |= 0xff000000;
            }
            else
            {
                *p &= 0x00ffffff;
            }
        }
    }

    delete[] opaque;
    ::DeleteDC(dib_dc);
    ::DeleteObject(dib);
    ::ReleaseDC(NULL, dc);

    return bitmap;
}

bool IconUtil::CreateIconFileFromSkBitmap(const SkBitmap& bitmap,
                                          const FilePath& icon_path)
{
    // Only 32 bit ARGB bitmaps are supported. We also make sure the bitmap has
    // been properly initialized.
    SkAutoLockPixels bitmap_lock(bitmap);
    if((bitmap.getConfig()!=SkBitmap::kARGB_8888_Config) ||
        (bitmap.height()<=0) || (bitmap.width()<=0) ||
        (bitmap.getPixels()==NULL))
    {
        return false;
    }

    // We start by creating the file.
    base::win::ScopedHandle icon_file(::CreateFileW(icon_path.value().c_str(),
        GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL));

    if(icon_file.Get() == INVALID_HANDLE_VALUE)
    {
        return false;
    }

    // Creating a set of bitmaps corresponding to the icon images we'll end up
    // storing in the icon file. Each bitmap is created by resizing the given
    // bitmap to the desired size.
    std::vector<SkBitmap> bitmaps;
    CreateResizedBitmapSet(bitmap, &bitmaps);
    DCHECK(!bitmaps.empty());
    size_t bitmap_count = bitmaps.size();

    // Computing the total size of the buffer we need in order to store the
    // images in the desired icon format.
    size_t buffer_size = ComputeIconFileBufferSize(bitmaps);
    unsigned char* buffer = new unsigned char[buffer_size];
    DCHECK(buffer != NULL);
    memset(buffer, 0, buffer_size);

    // Setting the information in the structures residing within the buffer.
    // First, we set the information which doesn't require iterating through the
    // bitmap set and then we set the bitmap specific structures. In the latter
    // step we also copy the actual bits.
    ICONDIR* icon_dir = reinterpret_cast<ICONDIR*>(buffer);
    icon_dir->idType = kResourceTypeIcon;
    icon_dir->idCount = bitmap_count;
    size_t icon_dir_count = bitmap_count - 1; // Note DCHECK(!bitmaps.empty())!
    size_t offset = sizeof(ICONDIR) + (sizeof(ICONDIRENTRY)*icon_dir_count);
    for(size_t i=0; i<bitmap_count; i++)
    {
        ICONIMAGE* image = reinterpret_cast<ICONIMAGE*>(buffer + offset);
        DCHECK_LT(offset, buffer_size);
        size_t icon_image_size = 0;
        SetSingleIconImageInformation(bitmaps[i], i, icon_dir, image, offset,
            &icon_image_size);
        DCHECK_GT(icon_image_size, 0U);
        offset += icon_image_size;
    }
    DCHECK_EQ(offset, buffer_size);

    // Finally, writing the data info the file.
    DWORD bytes_written;
    bool delete_file = false;
    if(!WriteFile(icon_file.Get(), buffer, buffer_size, &bytes_written, NULL) ||
        bytes_written!=buffer_size)
    {
        delete_file = true;
    }

    ::CloseHandle(icon_file.Take());
    delete[] buffer;
    if(delete_file)
    {
        bool success = base::Delete(icon_path, false);
        DCHECK(success);
    }

    return !delete_file;
}

bool IconUtil::PixelsHaveAlpha(const uint32* pixels, size_t num_pixels)
{
    for(const uint32* end=pixels+num_pixels; pixels!=end; ++pixels)
    {
        if((*pixels&0xff000000) != 0)
        {
            return true;
        }
    }

    return false;
}

void IconUtil::InitializeBitmapHeader(BITMAPV5HEADER* header, int width,
                                      int height)
{
    DCHECK(header);
    memset(header, 0, sizeof(BITMAPV5HEADER));
    header->bV5Size = sizeof(BITMAPV5HEADER);

    // Note that icons are created using top-down DIBs so we must negate the
    // value used for the icon's height.
    header->bV5Width = width;
    header->bV5Height = -height;
    header->bV5Planes = 1;
    header->bV5Compression = BI_RGB;

    // Initializing the bitmap format to 32 bit ARGB.
    header->bV5BitCount = 32;
    header->bV5RedMask = 0x00FF0000;
    header->bV5GreenMask = 0x0000FF00;
    header->bV5BlueMask = 0x000000FF;
    header->bV5AlphaMask = 0xFF000000;

    // Use the system color space.  The default value is LCS_CALIBRATED_RGB, which
    // causes us to crash if we don't specify the approprite gammas, etc.  See
    // <http://msdn.microsoft.com/en-us/library/ms536531(VS.85).aspx> and
    // <http://b/1283121>.
    header->bV5CSType = LCS_WINDOWS_COLOR_SPACE;

    // Use a valid value for bV5Intent as 0 is not a valid one.
    // <http://msdn.microsoft.com/en-us/library/dd183381(VS.85).aspx>
    header->bV5Intent = LCS_GM_IMAGES;
}

void IconUtil::SetSingleIconImageInformation(const SkBitmap& bitmap,
                                             size_t index,
                                             ICONDIR* icon_dir,
                                             ICONIMAGE* icon_image,
                                             size_t image_offset,
                                             size_t* image_byte_count)
{
    DCHECK(icon_dir != NULL);
    DCHECK(icon_image != NULL);
    DCHECK_GT(image_offset, 0U);
    DCHECK(image_byte_count != NULL);

    // We start by computing certain image values we'll use later on.
    size_t xor_mask_size, bytes_in_resource;
    ComputeBitmapSizeComponents(bitmap, &xor_mask_size, &bytes_in_resource);

    icon_dir->idEntries[index].bWidth = static_cast<BYTE>(bitmap.width());
    icon_dir->idEntries[index].bHeight = static_cast<BYTE>(bitmap.height());
    icon_dir->idEntries[index].wPlanes = 1;
    icon_dir->idEntries[index].wBitCount = 32;
    icon_dir->idEntries[index].dwBytesInRes = bytes_in_resource;
    icon_dir->idEntries[index].dwImageOffset = image_offset;
    icon_image->icHeader.biSize = sizeof(BITMAPINFOHEADER);

    // The width field in the BITMAPINFOHEADER structure accounts for the height
    // of both the AND mask and the XOR mask so we need to multiply the bitmap's
    // height by 2. The same does NOT apply to the width field.
    icon_image->icHeader.biHeight = bitmap.height() * 2;
    icon_image->icHeader.biWidth = bitmap.width();
    icon_image->icHeader.biPlanes = 1;
    icon_image->icHeader.biBitCount = 32;

    // We use a helper function for copying to actual bits from the SkBitmap
    // object into the appropriate space in the buffer. We use a helper function
    // (rather than just copying the bits) because there is no way to specify the
    // orientation (bottom-up vs. top-down) of a bitmap residing in a .ico file.
    // Thus, if we just copy the bits, we'll end up with a bottom up bitmap in
    // the .ico file which will result in the icon being displayed upside down.
    // The helper function copies the image into the buffer one scanline at a
    // time.
    //
    // Note that we don't need to initialize the AND mask since the memory
    // allocated for the icon data buffer was initialized to zero. The icon we
    // create will therefore use an AND mask containing only zeros, which is OK
    // because the underlying image has an alpha channel. An AND mask containing
    // only zeros essentially means we'll initially treat all the pixels as
    // opaque.
    unsigned char* image_addr = reinterpret_cast<unsigned char*>(icon_image);
    unsigned char* xor_mask_addr = image_addr + sizeof(BITMAPINFOHEADER);
    CopySkBitmapBitsIntoIconBuffer(bitmap, xor_mask_addr, xor_mask_size);
    *image_byte_count = bytes_in_resource;
}

void IconUtil::CopySkBitmapBitsIntoIconBuffer(const SkBitmap& bitmap,
                                              unsigned char* buffer,
                                              size_t buffer_size)
{
    SkAutoLockPixels bitmap_lock(bitmap);
    unsigned char* bitmap_ptr = static_cast<unsigned char*>(bitmap.getPixels());
    size_t bitmap_size = bitmap.height() * bitmap.width() * 4;
    DCHECK_EQ(buffer_size, bitmap_size);
    for(size_t i=0; i<bitmap_size; i+=bitmap.width()*4)
    {
        memcpy(buffer+bitmap_size-bitmap.width()*4-i,
            bitmap_ptr+i, bitmap.width()*4);
    }
}

void IconUtil::CreateResizedBitmapSet(const SkBitmap& bitmap_to_resize,
                                      std::vector<SkBitmap>* bitmaps)
{
    DCHECK(bitmaps != NULL);
    DCHECK(bitmaps->empty());

    bool inserted_original_bitmap = false;
    for(size_t i=0; i<arraysize(icon_dimensions_); i++)
    {
        // If the dimensions of the bitmap we are resizing are the same as the
        // current dimensions, then we should insert the bitmap and not a resized
        // bitmap. If the bitmap's dimensions are smaller, we insert our bitmap
        // first so that the bitmaps we return in the vector are sorted based on
        // their dimensions.
        if(!inserted_original_bitmap)
        {
            if((bitmap_to_resize.width()==icon_dimensions_[i]) &&
                (bitmap_to_resize.height()==icon_dimensions_[i]))
            {
                bitmaps->push_back(bitmap_to_resize);
                inserted_original_bitmap = true;
                continue;
            }

            if((bitmap_to_resize.width()<icon_dimensions_[i]) &&
                (bitmap_to_resize.height()<icon_dimensions_[i]))
            {
                bitmaps->push_back(bitmap_to_resize);
                inserted_original_bitmap = true;
            }
        }
        bitmaps->push_back(skia::ImageOperations::Resize(
            bitmap_to_resize, skia::ImageOperations::RESIZE_LANCZOS3,
            icon_dimensions_[i], icon_dimensions_[i]));
    }

    if(!inserted_original_bitmap)
    {
        bitmaps->push_back(bitmap_to_resize);
    }
}

size_t IconUtil::ComputeIconFileBufferSize(const std::vector<SkBitmap>& set)
{
    DCHECK(!set.empty());

    // We start by counting the bytes for the structures that don't depend on the
    // number of icon images. Note that sizeof(ICONDIR) already accounts for a
    // single ICONDIRENTRY structure, which is why we subtract one from the
    // number of bitmaps.
    size_t total_buffer_size = sizeof(ICONDIR);
    size_t bitmap_count = set.size();
    total_buffer_size += sizeof(ICONDIRENTRY) * (bitmap_count - 1);
    DCHECK_GE(bitmap_count, arraysize(icon_dimensions_));

    // Add the bitmap specific structure sizes.
    for(size_t i=0; i<bitmap_count; i++)
    {
        size_t xor_mask_size, bytes_in_resource;
        ComputeBitmapSizeComponents(set[i], &xor_mask_size, &bytes_in_resource);
        total_buffer_size += bytes_in_resource;
    }
    return total_buffer_size;
}

void IconUtil::ComputeBitmapSizeComponents(const SkBitmap& bitmap,
                                           size_t* xor_mask_size,
                                           size_t* bytes_in_resource)
{
    // The XOR mask size is easy to calculate since we only deal with 32bpp
    // images.
    *xor_mask_size = bitmap.width() * bitmap.height() * 4;

    // Computing the AND mask is a little trickier since it is a monochrome
    // bitmap (regardless of the number of bits per pixels used in the XOR mask).
    // There are two things we must make sure we do when computing the AND mask
    // size:
    //
    // 1. Make sure the right number of bytes is allocated for each AND mask
    //    scan line in case the number of pixels in the image is not divisible by
    //    8. For example, in a 15X15 image, 15 / 8 is one byte short of
    //    containing the number of bits we need in order to describe a single
    //    image scan line so we need to add a byte. Thus, we need 2 bytes instead
    //    of 1 for each scan line.
    //
    // 2. Make sure each scan line in the AND mask is 4 byte aligned (so that the
    //    total icon image has a 4 byte alignment). In the 15X15 image example
    //    above, we can not use 2 bytes so we increase it to the next multiple of
    //    4 which is 4.
    //
    // Once we compute the size for a singe AND mask scan line, we multiply that
    // number by the image height in order to get the total number of bytes for
    // the AND mask. Thus, for a 15X15 image, we need 15 * 4 which is 60 bytes
    // for the monochrome bitmap representing the AND mask.
    size_t and_line_length = (bitmap.width() + 7) >> 3;
    and_line_length = (and_line_length + 3) & ~3;
    size_t and_mask_size = and_line_length * bitmap.height();
    size_t masks_size = *xor_mask_size + and_mask_size;
    *bytes_in_resource = masks_size + sizeof(BITMAPINFOHEADER);
}